An interest rate option which applies one rate for part of the option’s life and another for the rest of its life. For example, an option that matures in 6 months may have a 5% rate for the first four months of its life and a 5.5% rate for the remaining two months.

A dual strike option could also refer to an option whose payoff is defined in the highest payoff of two options. These options, of course, have two different underlyings and two strike prices. Therefore, the payoff of a dual strike call, for example, is equal to the maximum between two payoffs: the payoff of the first underlying minus its strike price, or the payoff of the second underlying minus its strike price.